Energy metering system for a fan coil

Abstract

Flow meters are disclosed that provide improved measurements of fluid flowing through fan coils. A flow meter includes a body that defines an inlet, an outlet, and a flow path extending along a longitudinal axis between the inlet and the outlet. The flow meter also includes transducers coupled to the body and exposed to the flow path defined by the body. The transducers are configured to transmit and receive a signal travelling through the flow path to measure a flow rate of fluid of the fan coil. The flow meter also includes one or more reflectors coupled to the body and exposed to the flow path defined by the body. Each of the one or more reflectors has a flat reflective surface that is exposed to the flow path and is configured to reflect the signal to relay the signal between the transducers.

What is claimed is: 
     
         1 . A flow meter for a fan coil, the flow meter comprising:
 a body that defines an inlet, an outlet, and a flow path extending along a longitudinal axis between the inlet and the outlet;   transducers coupled to the body and exposed to the flow path defined by the body, the transducers configured to transmit and receive a signal travelling through the flow path to measure a flow rate of fluid of the fan coil; and   one or more reflectors coupled to the body and exposed to the flow path defined by the body, each of the one or more reflectors has a flat reflective surface that is exposed to the flow path and is configured to reflect the signal to relay the signal between the transducers.   
     
     
         2 . The flow meter of  claim 1 , wherein the signal transmitted and received by the transducers is an ultrasonic signal. 
     
     
         3 . The flow meter of  claim 1 , wherein the transducers include a transmitter and a receiver, wherein the transmitter is configured to transmit the signal in a direction toward a first of the one or more reflectors, wherein the receiver is configured to receive the signal reflected by each of the one or more reflectors. 
     
     
         4 . The flow meter of  claim 1 , further comprising a controller in communication with the transducers, wherein the controller is configured to determine the flow rate of the fluid based on a measurement of a travel time of the signal between the transducers. 
     
     
         5 . The flow meter of  claim 4 , wherein, to prevent interference from affecting the measurement of the travel time of the signal, the controller is configured to delay sampling of the signal by a first of the transducers to start a predetermined period of time after a second of the transducers sends the transmits the signal. 
     
     
         6 . The flow meter of  claim 1 , wherein the flat reflective surface of each of the one or more reflectors extends parallel to the longitudinal axis of the body. 
     
     
         7 . The flow meter of  claim 1 , wherein each of the transducers is oriented at a predefined angle relative to the longitudinal axis, and wherein the predefined angle of each of the transducers is based on the material composition of the fluid and the one or more reflectors to enable total internal reflection of the signal off each of the one or more reflectors. 
     
     
         8 . The flow meter of  claim 7 , wherein each of the one or more reflectors is formed of copper and the predefined angle at which each of the transducers is oriented is greater than about 45 degrees. 
     
     
         9 . The flow meter of  claim 1 , wherein the one or more reflectors include three reflectors each of which is positioned between the transducers relative to the longitudinal axis, and wherein the three reflectors are configured to reflect the signal in sequence to form a W-shaped signal path of the signal between the transducers. 
     
     
         10 . The flow meter of  claim 1 , wherein none of the transducers and none of the one or more reflectors are positioned within or extend into the flow path defined by the body. 
     
     
         11 . A flow meter for a fan coil, the flow meter comprising:
 a body that defines an inlet, an outlet, a flow path extending along a longitudinal axis between the inlet and the outlet, transducer openings, and reflector openings;   transducers positioned within the transducer openings to expose the transducers to the flow path defined by the body, the transducers being removably coupled to the body, the transducers being configured to transmit and receive a signal travelling through the flow path to measure a flow rate of fluid of the fan coil;   reflectors positioned within the reflector openings to expose the reflectors to the flow path defined by the body, the reflectors being removably coupled to the body, each of the reflectors having a flat reflective surface that is exposed to the flow path and is configured to reflect the signal to relay the signal between the transducers; and   plates removably coupled to the body to removably couple the transducers and the reflectors to the body.   
     
     
         12 . The flow meter of  claim 11 , further comprising seals each of which is configured to form a sealed coupling between the body and one of the transducers or one of the reflectors. 
     
     
         13 . The flow meter of  claim 11 , wherein at least one of the plates defines a flat outer surface to enable the body to securely rest on an adjacent object for support. 
     
     
         14 . The flow meter of  claim 11 , wherein the body further includes a first wall and second walls opposite the first wall, wherein the second walls define the transducer openings. 
     
     
         15 . The flow meter of  claim 14 , wherein the first wall defines two of the reflector openings into which two of the reflectors extend and the second walls define one of the reflector openings, and wherein the reflectors include three reflectors that are positioned relative to the transducers to form a W-shaped signal path of the signal between the transducers. 
     
     
         16 . The flow meter of  claim 14 , wherein the plates include first and second plates configured to couple the transducers to respective walls of the second walls. 
     
     
         17 . The flow meter of  claim 16 , wherein the plates include:
 a third plate configured to couple one of the reflectors to a respective one of the second walls; and   a fourth plate configured to couple two of the reflectors to the first wall.